Model 193-6 Survey Meter Technical Manual Section 4
Ludlum Measurements, Inc. Page 4-1 August 2023
Identification of Controls and
Functions
Range Selector Switch: a six-position switch marked OFF, BAT, ×1000,
×100, ×10 and ×1. When placed in the BAT position, battery charge
status is indicated on the meter face. Moving the range selector switch to
one of the range multiplier positions (×1000, ×100, ×10 or ×1) provides
the operator with an overall range of 0-1000 µR/hr when used in
conjunction with a 0-1 µR/hr meter face. To determine the actual
reading, multiply the scale reading by the range multiplier.
AUD ON-OFF Toggle Switch: When placed in the ON position this
switch activates the unimorph speaker, located on the left side of the
instrument. The frequency of the clicks is relative to the rate of the
incoming pulses. The higher the rate is, the higher the audio frequency.
The audio should be turned OFF when not required, to reduce battery
drain.
F-S Toggle Switch: provides meter response. Selecting the fast, ˝F,˝
position of the toggle switch provides 90% of full scale meter deflection
in approximately four seconds. In the slow, ˝S,˝ position, 90% of full-
scale meter deflection takes approximately 22 seconds. In the ˝F˝
position there is fast response and large meter deviation. The ˝S˝
position should be used for slow response and damped meter deviation.
ALARM Light: When the meter pointer deflects above the alarm set
point, this red lamp illuminates. This lamp flashes when radiation levels
rise above background. In both cases the visual alarms will be
accompanied by an audible alarm.
RESET Pushbutton: When depressed, this switch provides a rapid
means of driving the meter needle to zero. Pressing RESET also causes an
eight-second background update. During these eight seconds, the
speaker will emit beeps and the ALARM light will flash every half-second.